Method of fire damper fabrication

ABSTRACT

The method of fabricating fire dampers which includes the steps of unrolling first sheet strip material from a coil and leading the sheet material through a first roll form to form a continuous blade configuration of a first size, feeding the blade configured strips in a first direction to a saw to cut the strip into segments, feeding the segments in the reverse direction to the saw to cut to the desired blade length, unrolling second sheet material and employing the said first roll form to roll blades of a second size, unrolling third sheet material and employing the first roll form to roll a frame length of a first size corresponding to the first blade size, unrolling fourth sheet material and die cutting blanks to predetermined length, feeding the blanks to a second roll form to form flanges in the blanks corresponding to the second blade size, and notching flanges of the frame at the corners thereof to thereby permit fabrication of fire dampers of two basic sizes in a minimum period of time and with a minimum of equipment and space requirements.

United States Patent [191 Kurz [ Nov. 6, 1973 METHOD OF FIRE DAMPER FABRICATION 22 Filed: May 30,1972

[21] Appl. No.: 258,065

[52] US. Cl 29/412, 29/416, 29/417,

29/434, 113/116 HA, 113/116 F, 113/116 BB [51] Int. Cl B23p 17/00 [58] Field of Search 29/412, 416, 417,

29/434; 113/116 F, 116 BB; 52/317, 475, 656, 631, 658; 287/189.36 D, 189.36 H, 30.92 .1, 30.92 A, 30.92 D; 160/1, 203, 206,

Primary Examiner-Charles W. Lanham Assistant Examiner-V. A. DiPalma Att0rney-Karl L. Spivak [57] ABSTRACT The method of fabricating fire dampers which includes the steps of unrolling first sheet strip material from a coil and leading the sheet material through a first roll form to form a continuous blade configuration of a first size, feeding the blade configured strips in a first direction to a saw to cut the strip into segments, feeding the segments in the reverse direction to the saw to cut to the desired blade length, unrolling second sheet material and employing the said first roll form to roll blades of a second size, unrolling third sheet material and employing the first roll form to roll a frame length ofa first size corresponding to the first blade size, unrolling fourth sheet material and die cutting blanks to predetermined length, feeding the blanks to a second roll form to form flanges in the blanks corresponding to the second blade size, and notching flanges of the frame at the corners thereof to thereby permit fabrication of fire dampers of two basic sizes in a minimum period of time and with a minimum of equipment and space requirements.

10 Claims, 12 Drawing Figures METHOD OF FIRE DAMPER FABRICATION BACKGROUND OF THE INVENTION This invention relates generally to the field of fire damper construction, and more particularly, is directed to a novel method of roll forming fire dampers of the interlocking, folding blade type.

Fire dampers of the interfolding blade type are well known in the art as exemplified by US. Pat. Nos. 3,273,632 and 3,327,766. Additional fire damper constructions of the general type which may be fabricated in accordance with the teaching of this invention have been disclosed in my copending patent applications, namely, Ser. No. 173,596, filed Aug. 20, 1971 entitled, Fire Damper Frames, Ser. No. 173,595, filed Aug. 20, 1971, entitled, Fire Damper Including Blade Locking Device; Ser. No. 183,818, filed Sept. 27, 1971, entitled, Horizontal Fire Damper; and Ser. No. 225,791, filed Feb. 14, 1972, entitled, Fire Damper Duct Adapter.

The foregoing patents and patent applications all disclose fire damper constructions which employ peripheral frames and interfolded blades which are operable within the frames to form a substantially air tight system to prevent the spread of fire within air ducts. U.S.. Pat. No. 3,327,766 to .Kurz discloses a damper frame which is of one piece construction and which is formed from a longitudinally extending blank and has a central web portion disposed between transversely spaced, upstanding flanges. The upstanding flanges are of substantially double blank thickness and are inwardly positioned to define a pair of outwardly disposed, peripheral, fire damper mounting regions. The upstanding flanges are notched at longitudinally spaced positions to form v-shaped or other configuration relief regions through which the blank is folded to form a conventional closed frame construction. The opposite ends of the longitudinally extending blank are provided with a plurality of transversely spaced, longitudinally extended fingers for frame end interlocking purposes. The frame at the other end of the blank is punched to provide tabs to interdigitate with the transverse space between the fingers at the other end so as to form a firm, easily assembled, interlocking structure for maintaining the fire damper frame in its closed condition. In the folded position, the inclined edges defined by each V-shaped notch abut each other in a manner to form continuous, transversely spaced flanges which in conjunction with the central web, define an inwardly directed channel. The interfolding blades function within the channel to form a curtain to close the opening defined by the fire damper frame in the event of fire.

In the preferred embodiment, the peripheral fire damper frame mounting regions are of double blank thickness and the channel section is of single blank thickness. In my copending application, Ser. No. 173,596, the peripheral mounting regions are illustrated of double blank thickness and the flanges are fabricated to single blank thickness. The present invention could be employed to fabricate a damper frame of either construction by proper employment of suitable roll form equipment.

SUMMARY OF THE INVENTION The present invention relates generally to a method of first damper fabrication, and more particularly, is directed to employing a first roll form and a second roll form in addition to suitable cutting and notching apparatus to manufacture fire damper blades and fire damper frames of two distinct sizes in a minimum period of time and by utilizing equipment which requires a minimum amount of floor space.

The method of fire damper fabrication in accordance with the present invention contemplates employing coils of thin sheet material of either steel or aluminum construction of suitable gauge to provide the necessary rigidity and fire resistance for the final product. The coil of sheet material is fed through a first roll form wherein the configuration of the interlocking blades is formed continuously to a saw wherein the continuous strip is cut into a convenient work length, for example twenty foot lengths. The twenty foot lengths are then fed back to the said saw wherein they are cut to the desired individual blade size.

The first roll form is provided with spacer plugs to permit the same equipment to be employed to roll blades of a smaller size and of a larger size using the same equipment in the same manner. Following the blade forming and cutting operations, the coil of elongate blade stock is replaced with a coil of frame sheet material. It is noteworthy that the first roll form is provided with outboard roll forming dies to roll form a continuous length of frame material of size corresponding to use with the smaller size blade. The elongate length of formed first frame material is fed to the saw wherein itis cut to a convenient size for more convenient handling. The lengths of cut frame material are then fed back to the same saw wherein they are cut to proper size for the size of the frame to be manufactured.

In order to form the frame to cooperate with the larger blade size, a fourth coil of suitably sized elongate strip material is employed and is fed rearwardly of the first roll form into an end notching device wherein the elongate strip is suitably end notched and is cut to length to accommodate the size of the frame being manufactured. The sized and notched elongate blanks are then fed through a second roll form to impress a pair of spaced, continuous flanges of size to accommodate the larger sized blades. After the flanges are formed, the sized and flanged strips are introduced to a punch press equipped with a notching die wherein the flanges are notched three times at the bending points to facilitate forming a rectangular, strong, and inexpensively made frame of the desired size. The end notches are interfolded to facilitate the frame closure in a strong, simply made junction.

It is therefore an object of the present invention to provide an improved method-of fire damper fabrication.

It is another object of the present invention to provide a novel method of fire damper fabrication which employs a minimum of mechanical equipment.

It is another object of the present invention to provide a novel method of fire damper dabrication which employs equipment that is compact in size and which utilizes the same basic equipment to produce fire dampers of two separate width requirements. I

It is another object of the present invention to provide a novel method of fire damper fabrication that utilizes conventional equipment in a unique manner to greatly reduce production costs.

It is another object of the present invention to provide a novel method of fire damper fabrication that is trouble-free in operation, inexpensive in setup and reliable in operation.

Other objects and a fuller understanding of the invention will be had by referring to the following description and claims of a preferred embodiment thereof, taken in conjunction with the accompanying drawings wherein like reference characters refer to similar parts throughout the several views and in which:

BRIEF DESCRIPTION OF THE DRAWINGS which can be employed to fabricate large size blades. v

FIG. 2A is a partial, top plan view similar to FIG. 2, showing the production facility arranged to fabricate thin line blades.

FIG. 2B is a top plan view of a production facility suitable to practice the method of the present invention which can be employed to fabricate large size frames.

FIG. 2C is a partial, top plan view similar to FIG. 2, showing the production facility arranged to fabricate thin line frames.

FIG. 3 is an enlarged, partial perspective view of a large fire damper blade which may be fabricated by utilizing the equipment in FIG. 2.

FIG. 3A is an enlarged perspective view of a small fire damper blade which may be fabricated by utilizing the equipment of FIG. 2A.

FIG. 4A is a top plan view of a elongate, large frame blank showing the ends notched.

ner such as by employing sheet metal screws which insert through the frame openings 16 and secure to the duct material (not shown). The fire damper blades 14 are interfolded in well-known manner to comprise a FIG. 4B is a perspective view of the blank of FIG. 4A

in which continuous, spaced flanges have been formed. FIG. 4C is a perspective view of the frame of FIG. 4B showing a plurality of pairs of notches in the flanges.

FIG. 5A is a perspective view of small frame with the flanges bent.

FIG. 5B is a perspective view of the frame member of FIG. 5A showing the flanges notched prior to fold- DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION type employing a folded, one piece, fire damper frame 12 having a plurality of interfolded fire damper blades 14 and which is manufactured in accordance with the teachings of this invention is set forth. The fire damper frame 12 is adapted to be secured to the duct work of air handling systems (not shown) in conventional manstack of reversely folded, continuous, interlocking blades which comprise a curtain for closing the open area 18 which is defined within the peripheral fire damper frame 12 in the event of fire. A pair of conventional straps 20 secure to the frame 12 and retain the blades 14 in the interfolded position as illustrated for normal operation by means of a fusible link 22. The fusible link 22 is fabricated of a low temperature fuse metal which melts when exposed to temperatures encountered when a fire occurs to separate the pair of straps 20 to thereby permit the blades 14 to close the open area 18 in the event of fire.

Referring now to FIG. 2, I show a schematic arrangement of equipment which can be employed to enable workmen to manufacture both a standard line and a thin line type of fire damper blade and frame at production rates in a minimum floor space requirement. As illustrated, a first roll form 24 positions near the feed end of a table or a workbench 26 to receive the leading end 28 of a coil of elongate, thin, strip material 30 as it unwinds from the coil 32 which is positioned in the axel 33. Preferably, 22 gauge galvinized sheet steel is employed in the manufacture of the damper frame and blades or such other thicknesses may be employed as required to meet necessary fire safety standards, such as the standards of Underwriters Laboratories, Inc. The strip material 30 is of suitable width to form blades 46 of large size for use within frames of standard size frames 12. The first roll form equipment 24 includes a central section 34 and an outboard section 36 which incorporates a separate set of dies which are capable of rolling an entirely different shape. In the embodiment illustrated, the central section 34 incorporates a plurality of pairs of spaced dies 38 which are utilized to roll the interfolded edges 40, 42 of the large fire damper blades 14. See FIG. 3. The same dies are employed to roll the interfolded edges 40a, 42a of the small fire damper blades 14a as in FIG. 3A. As hereinbefore stated, fire dampers of the interfolded blade type are normally fabricated to a standard size and to a thin line size, depending upon job requirements and overall fire damper size. By employing spacers 44, the pairs of spaced dies 38 can readily be spaced wider apart as illustrated in FIG. 2 to form fire damper blades 14 of the wider size for use in the standard type of fire damper. By removing the spacers 44, the pairs of dies 38 can then approach closer together to thereby employ the same basic roll form equipment to roll fire damper blades 14a of the thin line size. It will be noted that the interfolded edges 40, 42 and 40a, 42a are rolled to precisely the same cross-sectional configuration for interfolding action and therefore the same dies 38 can be utilized. Only the dimensions of the fire damper blade web 46, 46a varies to produce fire damper blades 14, 14a of the desired width for the intended end purpose. Thus, a single roll form 24 can be utilized to produce fire damper blades 14, 14a of a first size or of a second size by varying the spacing between the pairs of dies 38, such as by employing spacers 44.

, In order to form the small blades 14a, the spacers 44 are removed as in FIG. 2A to permit the pairs of dies 38 to move closer together. A coil 32a of narrower stock feeds elongate sheet steel 30a to the first roll form 24. The leading edge 28a of the material 30a is introduced to the roll form 24 wherein blades having configuration as illustrated in FIG. 3a are produced.

A pair of spaced guides 48, 50 position downstream of the first roll form 24 and upwardly extend from the surface 52 of the table 26. The guides 48, 50 direct the newly rolled continuous fire blade strips toward the saw 54 for cutting purposes. Preferably, the roller blade strips 15 are cut into convenient size lengths, for example twenty foot lengths for convenience of handling. The saw 54 has transverse movement relative to the longitudinal orientation of the guides 48,50 and is of conventional design of any known manufacture suitable to cut thin sheet steel.

Following cutting by the saw 54 into foot lengths 17, the lengths are fed downstream to a second table 56 until a predetermined quantity of fire damper blade lengths 17, have been rolled. The lengths are then fed upstream from the table 56 to the table 26 between the guides 48, 50 toward the saw 54. In this instance, the saw 54 is utilized to transversely cut the blade lengths into the desired blade final size for use within the fire damper frames 12 in conventional manner.

When it is desired to employ the apparatus to fabricate a thin line fire damper frame, the damper blade coil 32 or 32a is replaced with a coil 320 of frame material of size suitable to form a thin line type of frame (see FIGS. 5A and 5B). The outboard section 36 of the first roll form 24 is provided with suitable dies 58 to roll form the thin line frame 60. The coil 320 is positioned on its axle 33c in alignment with the outboard section 36 in a manner to introduce the leading edge 280 to the dies 58. The dies 58 serve to bend the transverse edges of the strip material inwardly to form a pair of spaced flanges 62, 64 and a interconnecting web section 66. The flanges 62, 64 serve as blade guides in the finished damper construction in conventional manner. The thin line blade material strip 300 feeds downstream through the outboard section 36 along the table surface 52 wherein the saw 54 can be employed to transversely cut the newly formed material to the desired size for fire damper fabrication purposes.

As illustrated in FIG. 2B, when it is desired to fabricate a fire damper frame 12 of standard configuration, such as shown in FIG. I, a coil of material 32b of suitable width is rotatively positioned on its axe] 33b between the first table 26 and the third table 68 which is located upstream relative to the first roll form 24. The elongate frame material 30 b is fed to a punch press 70 from the coil 32b. The punch press 70 serves the dual purposes of cutting the elongate sheet material into properly sized blanks 72 and simultaneously cutting a plurality of transversely spaced fingers 74 at one end 81 of the blank 72 and a pair of tab extensions 78, 80 at the second end 82 of the blank 72. At the same time, elongate transverse slits 84 are punched at the junction of the tab extensions 78, 80 with the main planar central web portion 86. See FIG. 4A. The slits 84 are in longitudinal alignment with the fingers 74 whereby the fingers will be disposed within the slits when the sheet metal blank is folded to form the fire damper frame 12 as best seen in FIG. 1.

The frame blanks 72 which have been properly cut to size and have the tab extensions 78, 80, transverse slits 84 and transversely spaced fingers 74 respectively cut at the ends 80, 81 thereof are moved about the surface of the third table 68 in the direction of the arrow 73 into longitudinal alignment with the second roll form 86. The blanks 72 are then fed one at a time through the roll form 86 wherein the spaced, longitudinal flanges 88, 90 are formed in the main planar central web portion 92 by employing well-known roll forming techniques. See FIG. 4B. Following the flange rolling operation, the flanged blanks are directed across the surface of the fourth table 94 into the feed of a second punch press 96 which is equipped in conventional manner with a suitable notching die to form three longitudinallly spaced pairs of transversely aligned notches 98, 100, 102 in the respective spaced flanges 88, 90. The pairs of notches are properly spaced to position atthe respectively corners 104, 106, 108 of the finished frame 12 to facilitate bending the frame to a rectangular configuration. In accordance with the teachings of my copending application, Ser. No. 173,596, filed Aug. 20, I971, the second punch press 96 may be employed to form various other types of die cut operations rather than simple V notching as illustrated in order to fabricate other frame reinforced constructions.

In accordance with the present invention, the thin line frame 60 may also have its respective flanges 62, 64 provided with pairs of longitudinally spaced notches 110, 112, 114 by employing the second punch press 96 in the usual manner.

Thus, by providing a plurality of suitably spaced tables, a first roll form of unique configuration, a second roll form and a pair of punch presses, fire damper blades and frames of both standard and thin line construction can be readily formed in continuous mannner in production quantities. The entire equipment requirements of the operation occupy a minimum of floor space and relatively unskilled labor may be employed to direct the various pieces of sheet material through the apparatus from one piece of equipment to the other for the necessary roll forming, sawing, punching and notching operations hereinbefore described.

In order to complete the fabrication of the various thin line and standard fire dampers, the completed frame members 60 or 75 are bent about the notches 110, 112, 114 or 98, 100, 102 to a rectangular configuration. Sufficient small or large blades 14a or 14 are interfolded to close the damper opening 18 and the interfolded blades are positioned within the channels 66 or 92 which are respectively defined between the small frame flanges 62, 64 or the large frame flanges 88, 90. With the blades positioned within the channels, the end closure of the frame members 60 or 75 can then be made in conventional manner. All required additional hardware (not shown) as may be required for the particular fire damper design can then be added in the usual manner.

I claim:

1. The method of fabricating fire dampers wherein a first roll form having a plurality of dies suitable to roll small blades and large blades is employed and wherein a second roll form to roll large frames is utilized, including the steps of A. spacing the dies of the first roll form apart a sufficient distance by inserting spacers to roll large blades of a first size; B. feeding a first web of elongate sheet metal material through the first rollform in a first direction to form a first continuous fire blade strip;

C. feeding the first continous fire blade strip to a saw and transversely cutting the continuous strip into large blades of suitable length;

D. removing the spacers to reduce space between the dies of the first roll form to roll small blades of a second size;

E. feeding a second web of elongate sheet metal material through the first roll form in a first direction to form a second continuous fire blade strip;

F. feeding the second continous fire blade strip to the said saw and transversely cutting the continuous strip into small blades of suitable length;

G. forming small fire damper frames and large fire damper frames and bending the frames to rectangular configuration; and

H. operatively associating the said small blades within the small fire damper frames and the large blades within the large fire damper frames.

2. The method of claim 1 and the additional step of feeding the said first and second continuous fire blade strips in a second direction to the said saw, the said saw cutting the strips in a direction transverse to the direction of travel.

3. The method of claim 1 and the additional steps of providing the first roll form with an outboard section having frame forming dies, feeding a third web of elongate sheet metal material in the first direction through the frame forming dies to form a continuous small frame strip of channel shaped cross sectional configuration having a web and a pair of spaced flanges and transversely cutting the shaped frame strip into small frame segments of suitable length.

4. The method of claim 3 and the additional steps of feeding a fourth web of elongate sheet metal material in a second direction to a punch press and cutting the strip into blanks having leading and trailing edges and being of suitable length to form large fire damper frame segments.

5. The method of claim 4 and the additional steps of shaping the leading and trailing edges of the blanks to predetermined configurations to provide interlocking constructions.

6. The method of claim 5 and the additional step of feeding the said blanks through a second roll form and rolling a pair of longitudinally aligned flanges, the said flanges being spaced inwardly from the respective transverse edges of the blank.

7. The method of claim 6 and the additional step of feeding the flanges of the small fire damper segments and large fire damper segments to a notching machine and punching a plurality of cuts in the flanges.

8. The method of claim 7 wherein each flange is cut in three longitudinally spaced locations, the said locations corresponding to the bends in the fire damper frames.

9. The method of claim 1 wherein the large blade strips and small blade strips are first cut into segments when travelling in the first direction.

10. The method of claim 9 and the additional step of feeding the segments in a second direction toward the said saw and cutting the segments into blade lengths of predetermined size. 

1. The method of fabricating fire dampers wherein a first roll form having a plurality of dies suitable to roll small blades and large blades is employed and wherein a second roll form to roll large frames is utilized, including the steps of A. spacing the dies of the first roll form apart a sufficient distance by inserting spacers to roll large blades of a first size; B. feeding a first web of elongate sheet metal material through the first roll form in a first direction to form a first continuous fire blade strip; C. feeding the first continous fire blade strip to a saw and transversely cutting the continuous strip into large blades of suitable length; D. removing the spacers to reduce space between the dies of the first roll form to roll small blades of a second size; E. feeding a second web of elongate sheet metal material through the first roll form in a first direction to form a second continuous fire blade strip; F. feeding the second continous fire blade strip to the said saw and transversely cutting the continuous strip into small blades of suitable length; G. forming small fire damper frames and large fire damper frames and bending the frames to rectangular configuration; and H. operatively associating the said small blades within the small fire damper frames and the large blades within the large fire damper frames.
 2. The method of claim 1 and the additional step of feeding the said first and second continuous fire blade strips in a second direction to the said saw, the said saw cutting the strips in a direction transverse to the direction of travel.
 3. The method of claim 1 and the additional steps of providing the first roll form with an outboard section having frame forming dies, feeding a third web of elongate sheet metal material in the first direction through the frame forming dies to form a continuous small frame strip of channel shaped cross sectional configuration having a web and a pair of spaced flanges and transversely cutting the shaped frame strip into small frame segments of suitable length.
 4. The method of claim 3 and the additional steps of feeding a fourth web of elongate sheet metal materIal in a second direction to a punch press and cutting the strip into blanks having leading and trailing edges and being of suitable length to form large fire damper frame segments.
 5. The method of claim 4 and the additional steps of shaping the leading and trailing edges of the blanks to predetermined configurations to provide interlocking constructions.
 6. The method of claim 5 and the additional step of feeding the said blanks through a second roll form and rolling a pair of longitudinally aligned flanges, the said flanges being spaced inwardly from the respective transverse edges of the blank.
 7. The method of claim 6 and the additional step of feeding the flanges of the small fire damper segments and large fire damper segments to a notching machine and punching a plurality of cuts in the flanges.
 8. The method of claim 7 wherein each flange is cut in three longitudinally spaced locations, the said locations corresponding to the bends in the fire damper frames.
 9. The method of claim 1 wherein the large blade strips and small blade strips are first cut into segments when travelling in the first direction.
 10. The method of claim 9 and the additional step of feeding the segments in a second direction toward the said saw and cutting the segments into blade lengths of predetermined size. 